Printing mechanism for typewriters having plural typewheels



Sept. 13, 1966 KAORU SEGAWA ETAL 3,

PRINTING MECHANISM FOR TYPEWRITERS HAVING PLURAL TYPEWHEELS Filed Oct. 12, 1964 2 Sheets-Sheet 1 J l g A TTORN Y5.

1 1966 KAORU SEGAWA ETAL 3,272,302

PRINTING MECHANISM FOR TYPEWRITERS HAVING PLURAL TYPEWHEELS Filed 001.. 12, 1964 2 Sheets-Sheet 2 13' I J: 2" N a IN V EN TORS KA ORU SEGA WA HIDE O OZAK/ United States Patent 3 272,302 PRINTING MECHAl JISM FOR TYPEWRITERS HAVING PLURAL TYPEWHEELS Kaoru Segawa and Hideo Ozaki, both of Tokyo, Japan, assignors to Nippon Electric Company, Limited, Tokyo, Japan, a corporation of Japan Filed Oct. 12, 1964, Ser. No. 403,285 Claims priority, application Japan, Oct. 17, 1963, 38/ 55,535 (:laims. (Cl. 197-50) This invention relates to a printing mechanism for typewriters and more particularly to such devices of the kind which perform printing by a swingably pivoted carriage and a typehead so mounted on the carriage as to be capable of travel to the left and right along the carriage, and so designed as to strike a platen located at the rear of the carriage by swinging displacement of the carriage during printing.

In the typewriter art, it is known to employ a typehead which carries a plurality of typewheels to accommodate a large number and kind of type characters. The known mechanisms of this kind, however, are of somewhat bulky and complex construction and the speed of printing is severely limited.

Accordingly, it is an object of this invention to provide a printing mechanism which employs a typehead of the multi-typewheel variety in a typewriter of the kind described herein, which features a simple and compact construction.

It is another object of the invention to provide a typewriter printing mechanism which is capable of extremely rapid type-selecting operation.

All of the objects, features and advantages of the invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a front elevation view of la pontion of a printing mechanism constructed in accordance with one embodiment of the invention,

FIG. 2 is a longitudinal section of the typehead portion of the printing mechanism illustrated in FIG. 1, and

FIG. 3 is a sectional view of the apparatus of FIG. 2 taken on the line 3-3 thereof.

In accordance with the invention, there is provided a printing mechanism having a typehead which employs a plurality of typewheels, each typewheel consisting of a'plurality of layers of type each arranged at different levels, each layer also having many type characters disposed circumferentially on the typewheel surface. Driving force means are also provided for selectively actuating the typehead and include a cylindrical sleeve and a central shaft associated therewith. The mechanism is operated in a manner whereby selection of one of the typewheels, selection of one of the layers or levels of a selected typewheel, and selection of a type character in the selected layer of the selected typewheel can be performed simultaneously by rotation and vertical motion of the cylindrical sleeve and notation of the central shaft.

Referring now to FIGS. 1 and 2, there is shown a carriage assembly which includes side plates 3 for supporting the carriage, the same being swingably movable on pivot studs 2 carried by bearing blocks which are installed at opposite ends of a base plate 1. This assembly also includes two horizontally disposed parallel shafts 4 and 5 and a horizontally disposed beam 6 parallel thereto, all of which are rigidly connected to the side plates 3. The assembly further includes horizontally disposed spline shafts 7, 8, 9 and 10, which are mounted for rotation in the side plates 3. Referring specifically to FIG. 1, it will 3,272,302 Patented Sept. 13, 1966 be understood that the typehead and the carriage, can swing back and forth together about the pivot stud 2. A framework -11 provides support for the typehead and is slidably mounted on the two parallel shafts 4 and 5 and the four spline shafts 7, 8, 9 and 10, and is movable to the left and right along the carriage.

Referring now specifically to FIG. 2, during printing, the carriage together with the framework 111 swings counterclockwise about the pivot stud 2, and thus desired type can strike the platen 12, one character being printed at a time. The spacing operation for properly locating the printing characters horizontally is performed through a conventional rack mechanism. However, specific description of the spacing operation and the mechanism therefor is omitted in this specification for simplicity and since these are unnecessary for a complete description of the invention.

The type selecting mechanism provided for the typehead of the present printing mechanism will now be described in detail. Referring again to FIG. 2, a cylindrical sleeve 20 is supported with a collar bushing 40 in the typehead supporting framework 1 1 in such a manner that this cylindrical sleeve can both rotate about its axis and move in the vertical direction. A plurality of multi-layer typewheels 15 are pivotally mounted on the surface of the upper flange of the cylindrical sleeve 20 and disposed point-symmetrically about the axis of the sleeve. Each typewheel includes a plurality of groupings of type characters 15a at spaced positions thereon, i.e., at different levels.

A central shaft 21 is disposed concentrically within the cylindrical sleeve 20, supported by an upper bearing 41, and a lower bearing 42, which is arranged with respect to the shaft 21 to permit rotary motion thereof about its axis, while preventing vertical motion. On an uppen spline part 44 of the central shaft 21 there is slidably mounted a spur gear 23 which meshes continuously with a plurality of companion gears 22 secured rigidly to the bottoms of the typewheels 15. At the lower end of the central shaft 21 there is secured a bevel gear 25 which meshes with and is driven by a driving bevel gear 24, the latter being slidably mounted on the spline shaft 7.

Near the lower end of the cylindrical sleeve 20, there is provided a series of annular grooves 46 cut into the peripheral surface of the sleeve. A vertically disposed rack 28, which constitutes a single body with a riser 27 engaging the grooves 46 meshes with a pinion 29 which is slidably mounted on the spline shaft 8, allowing the rack 28 to move vertically.

A driven sector gear 32 is fixed to a shaft 35, as is also a driven bevel gear 33, and these are supported for rotation by a bracket 31 clamped to the front of the framework 11. The sector gear 32 meshes in a slidable manner with a spline 30 disposed on the cylindrical sleeve 20 intermediate its ends. The driven bevel gear 33 meshes with a driving bevel gear 34 which is slidably mounted on the spline shaft 9. One end of the gear boss of the gear 34 is fitted into an aperture in a gear support 36, this support being clamped rigidly to the surface of the framework 11.

The type selecting operation of this printing mechanism Will now be described. Referring particularly to FIG. 2, if the spline shaft 9 is caused to rotate by any suitable conventional means, such as a link and cam mechanism, not shown, the bevel gears 34 and 33, sector gear 32, and the spline 30 of the cylindrical sleeve 20 will be rotated, causing the sleeve 20 to rotate about its axis and a selected typewheel 15 to be rotated to the printing position facing the platen 12.

The rotation of the spline shaft 8 causes the cylindrical sleeve 20 and the typewheels 15 to move together in an upward or downward direction'by mean-s of the rack 28 and pinion 29. The typewheels 15 will descend when the spline shaft 8 is turned clockwise and will ascend when the shaft is turned counterclockwise as seen in FIG. 2. In the particular embodiment described, the letter and number print characters are arranged in four layers at four different levels on the cylindrical suface of each typewheel 15. It will be undestood therefore that rotation is transmitted to the spline shaft 8 after one of the four. different degrees of rotation assigned to each typewheel has been selected so that a required type layer may occupy a height corresponding to the printing position of the platen 12.

Next, by causing the spline shaft 7 to rotate by suitable conventional drive means, the bevel gears 24 and 25 will be rotated, causing rotation of the central shaft 21. This initiates simultaneous rotation of all the typewheels 15 through the spur gear 23 which is slidably mounted on the spline portion 44 of the shaft 21, and the three companion gears 22 that mesh with spur gear 23, regardless of the vertical position of the sleeve 20.

In accordance with the particular embodiment described herein, sixteen characters are arranged in each of the four layers on the cylindical surface of each typewheel 15. Therefore, any one of sixteen different degrees of rotation will be transmitted selectively to the spline shaft 7, the particular angular rotation being selected to print the desired character with which it is associated.

To sum up the foregoing description, selection of one of the typewheels 15 is effected by rotation of the cylindrical sleeve 20, selection of any level of each typewheel is effected by vertical movement of the sleeve 20, and selection of a type or character from any given layer or level is effected by rotation of the central shaft 21. These selecting operations occur simultaneously through the three driving means including the spline shafts 9, 8 and 7, which operate independently from one another.

Since the type selecting operation of the printing mechanism according to this invention is performed by the vertically disposed cylindrical sleeve 20 carrying the typewheels and the central shaft 21 disposed within this sleeve, it will be evident that the novel construction herein is extremely compact and simple. Additionally, this construction makes possible a very rapid type selecting operation, so that increased printing speed and higher efficiency is achieved over that possible with prior art mechanisms.

While the foregoing description sets forth the principles of the invention in connection with specific apparatus, it is to be understood that the description is made only by Way of example and not as a limitation of the scope of the invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

1. A printing mechanism for a typwriter comprising a carriage and a typehead mounted on said carriage and movable thereon,

a plurality of typewheels mounted in said typehead, said typewheels each having a plurality of groups of type characters at spaced positions thereon,

a vertically disposed cylindrical sleeve pivotally mounted on said carriage to permit both rotary and vertical motion thereof, said typewheels being supported on said cylindrical sleeve,

a central shaft disposed within said cylindrical sleeve and mounted so as to permit rotary motion thereof,

a gear mechanism between said central shaft and each of said typewheels for transmitting rotation of said central shaft to all of the typewheels simultaneously at any vertical position of said cylindrical sleeve,

a rotary driving force transmission means for said cylindrical sleeve,

- a vertical driving force transmission means for said cylindrical sleeve including circumferential flanges on said sleeve and means engaging said flanges to impart vertical motion to said sleeve while allowing rotation of the same, and a rotary driving force transmission means for said central shaft regardless of the rotary and vertical motion of said cylindrical sleeve, whereby selection of one of the typewheels, selection of a group of a selected typewheel, and selection of an individual type character in the selected layer of the selected typewheelcan be performed simultaneously by rotation of said cylindrical sleeve, vertical motion of said cylindrical sleeve, and rotation of said central shaft.

2. The invention defined in claim 1 wherein said vertical driving force transmission means for said cylindrical sleeve further includes a rack and pinion mechanism.

3. The invention defined in claim 1 wherein said gear mechanism includes a gear mounted for rotation about the axis of said central shaft, said gear being slidably engageable with a spline on the upper portion of said central shaft, whereby a driving force is transmitted from said central shaft to said gear at any vertical position of said shaft.

4. A printing mechanism for a typewriter comprising a carriage and a platen mounted adjacent thereto,

a frame member mounted on said carriage, said frame member being capable of movement along the length of said carriage,

a typehead mounted onsaid frame member for printing characters on a type receiving medium on said platen,

a vertically disposed cylindrical sleeve pivotally mounted in said frame member to permit both rotary and vertical motion thereof, said sleeve having a flange at its upper end,

a plurality of typewheels mounted for rotation on said flange, said typewheels being disposed symmetrically about the central axis of said cylindrical sleeve,

said typewheels each having a plurality of groupings of type characters spaced at different levels thereon,

a central shaft disposed within said cylindrical sleeve and pivotally mounted so as to permit rotary motion thereof,

a gear mechanism between said central shaft and each of said typewheels for transmitting rotation of said central shaft to all of the typewheels simultaneously regardless of the vertical position of said cylindrical sleeve,

a rotary driving force transmission means for said cylindrical sleeve,

a vertical driving force transmission means for said cylindrical sleeve including circumferential flanges on said sleeve and means engaging said flanges to impart vertical motion to said sleeve while allowing rotation of the same,

and a rotary driving force transmission means for said central shaft regardless of the rotary and vertical motion of said cylindical sleeve, whereby selection of one of the typewheels, selection of one of the levels of a selected typewheel, and selection of an individual type character in the selected layer of the selected typewheel can be performed simultaneously by rotation of said cylindrical sleeve, vertical motion of said cylindrical sleeve, and rotation of said central shaft.

5. A printing mechanism for a typewriter wherein a typehead is slidably mounted on a carriage so as to move to the left or right along said carriage to perform printing 'when it strikes a platen located at the rear of said carriage by swinging movement of said carriage in the direction perpendicular to the aforementioned movement of said typehead, said mechanism comprising a framework for supporting the typehead and mounted on the carriage so as to be capable of movement to the left or right,

a vertically disposed cylindrical sleeve pivotally mounted in said framework to permit both rotary and vertical motion thereof, said sleeve having a flange,

plurality of multi-layer typewheels point-symmetrically arranged about the central axis of said cylincentral shaft regardless of the rotary and vertical motion of said cylindical sleeve, whereby selection of one of the typewheels, selection of one of the levels of a selected typewheels, and selection of a type in drical sleeve and pivotally mounted on the flange of 5 the selected layer of the selected typewheel can be said cylindrical sleeve, performed simultaneously by rotation of said cylincentral shaft disposed Within said cylindrical sleeve drical sleeve, vertical motion of said cylindrical and pivotally mounted so as to permit rotary motion sleeve, and rotation of said central shaft.

thereof,

gear mechanism for transmission of rotation of said 10 References Clted y the Examlnel central shaft to all of the typewheels simultaneously regardless of the vertical position of said cylindrical UNITED STATES PATENTS leeve a rotary driving force transmission means for said 1 figi 155 1 cylindrical sleeve, 15 i 1 a vertical driving force transmission means for said FOREIGN PATENTS cylindrical sleeve including circumferential flanges on said sleeve and means engaging said flanges to impart 273,713 5/1914 yvertical motion to said sleeve while allowing rotation 5 7785 9 6/1933 Germany;

of the ame 20 Great Brltall'l.

a rack and pinion directly coupled to said latter mentioned means for producing the vertical motion of said cylindrical sleeve,

and a rotary driving force transmission means for said DAVID KLEIN, Primary Examiner.

ROBERT E. PULFREY, Examiner.

EDGAR S. BURR, Assistant Examiner. 

1. A PRINTING MECHANISM FOR A TYPWRITER COMPRISING A CARRIAGE AND A TYPEHEAD MOUNTED ON SAID CARRIAGE AND MOVABLE THEREON, A PLURALITY OF TYPEWHEELS MOUNTED IN SAID TYPEHEAD, SAID TYPEWHEELS EACH HAVING A PLURALITY OF GROUPS OF TYPE CHARACTERS AT SPACED POSITIONS THEREON, A VERTICALLY DISPOSED CYLINDRICAL SLEEVE PIVOTALLY MOUNTED ON SAID CARRIAGE TO PERMIT BOTH ROTARY AND VERTICAL MOTION THEREOF, SAID TYPEWHEELS BEING SUPPORTED ON SAID CYLINDRICAL SLEEVE, A CENTRAL SHAFT DISPOSED WITHIN SAID CYLINDRICAL SLEEVE AND MOUNTED SO AS TO PERMIT ROTARY MOTION THEREOF, A GEAR MECHANISM BETWEEN SAID CENTRAL SHAFT AND EACH OF SAID TYPEWHEELS FOR TRANSMITTING ROTATION OF SAID CENTRAL SHAFT TO ALL OF THE TYPEWHEELS SIMULTANEOUSLY AT ANY VERTICAL POSITION OF SAID CYLINDRICAL SLEEVE, A ROTARY DRIVING FORCE TRANSMISSION MEANS FOR SAID CYLINDRICAL SLEEVE, 